The relationships between brain regions and forelimb dexterity in marsupials (Marsupialia): a comparative test of the principle of proper mass

2000 ◽  
Vol 48 (1) ◽  
pp. 99 ◽  
Author(s):  
Andrew N. Iwaniuk ◽  
John E. Nelson ◽  
Ian Q. Whishaw

A behavioural index of forelimb dexterity and comparative statistics were used to analyse the relationships between proximal (shoulder, upper and lower forelimb) and distal (wrist, forepaw, digits) forelimb dexterity and four aspects of brain morphology (overall brain, cortex, cerebellum and telencephalon sizes) in 18 species of marsupials. On the basis of the principle of proper mass, it was expected that an increase in forelimb dexterity (either proximal or distal) would be positively correlated with the size of the brain and the three brain components. Using independent contrast analysis to remove the effects of phylogeny revealed three significant correlations between: cortex size and distal dexterity, cerebellum size and proximal dexterity, and telencephalon size and distal dexterity. The relationship between cortex size and distal dexterity was subsequently corroborated by Spearman rank correlations. These results suggest that the execution of finely coordinated forelimb movements may not be dependent upon overall brain size, but may be dependent upon the size of brain components, thus supporting the principle of proper mass.

2003 ◽  
Vol 26 (5) ◽  
pp. 556-557 ◽  
Author(s):  
Emmanuel Gilissen ◽  
Thierry Smith

Fossil remains witness the relationship between the appearance of the middle ear and the expansion of the brain in early mammals. Nevertheless, the lack of detachment of ear ossicles in the mammaliaform Morganucodon, despite brain enlargement, points to other factors that triggered brain expansion in early mammals. Moreover, brain expansion in some early mammalian groups seems to have favored brain regions other than the cortex.


2020 ◽  
Vol 70 (4) ◽  
pp. 401-416
Author(s):  
Mao Jun Zhong ◽  
Long Jin ◽  
Jian Ping Yu ◽  
Wen Bo Liao

Abstract The expensive tissue hypothesis predicts a trade-off between investments in the brain and other energetically costly organs due to the costs associated with their growth and maintenance within the finite energy resources available. However, few studies address the strength of relationships between brain size and investments in precopulatory (ornaments and armaments) and postcopulatory (testes and ejaculates) sexual traits. Here, in a broad comparative study, we tested the prediction that the relationship between brain size and investment in sexual traits differs among taxa relative to the importance of sperm competition within them. We found that brain size was negatively correlated with sexual size dimorphism (SSD) in anurans and primates, and it tended to decrease with SSD in ungulates and cetaceans. However, brain size did not covary significantly with armaments (e.g., canine length, horn, antler, and muscle mass). Brain size was not correlated with postcopulatory sexual traits (testes and ejaculates). The intensity of covariance between brain size and precopulatory sexual traits decreased with increasing relative testis size.


2019 ◽  
Vol 69 (6) ◽  
pp. 589-611
Author(s):  
Elissa C Kranzler ◽  
Ralf Schmälzle ◽  
Rui Pei ◽  
Robert C Hornik ◽  
Emily B Falk

Abstract Campaign success is contingent on adequate exposure; however, exposure opportunities (e.g., ad reach/frequency) are imperfect predictors of message recall. We hypothesized that the exposure-recall relationship would be contingent on message processing. We tested moderation hypotheses using 3 data sets pertinent to “The Real Cost” anti-smoking campaign: past 30-day ad recall from a rolling national survey of adolescents aged 13–17 (n = 5,110); ad-specific target rating points (TRPs), measuring ad reach and frequency; and ad-elicited response in brain regions implicated in social processing and memory encoding, from a separate adolescent sample aged 14–17 (n = 40). Average ad-level brain activation in these regions moderates the relationship between national TRPs and large-scale recall (p < .001), such that the positive exposure-recall relationship is more strongly observed for ads that elicit high levels of social processing and memory encoding in the brain. Findings advance communication theory by demonstrating conditional exposure effects, contingent on social and memory processes in the brain.


2016 ◽  
Vol 113 (9) ◽  
pp. 2532-2537 ◽  
Author(s):  
Sarah Benson-Amram ◽  
Ben Dantzer ◽  
Gregory Stricker ◽  
Eli M. Swanson ◽  
Kay E. Holekamp

Despite considerable interest in the forces shaping the relationship between brain size and cognitive abilities, it remains controversial whether larger-brained animals are, indeed, better problem-solvers. Recently, several comparative studies have revealed correlations between brain size and traits thought to require advanced cognitive abilities, such as innovation, behavioral flexibility, invasion success, and self-control. However, the general assumption that animals with larger brains have superior cognitive abilities has been heavily criticized, primarily because of the lack of experimental support for it. Here, we designed an experiment to inquire whether specific neuroanatomical or socioecological measures predict success at solving a novel technical problem among species in the mammalian order Carnivora. We presented puzzle boxes, baited with food and scaled to accommodate body size, to members of 39 carnivore species from nine families housed in multiple North American zoos. We found that species with larger brains relative to their body mass were more successful at opening the boxes. In a subset of species, we also used virtual brain endocasts to measure volumes of four gross brain regions and show that some of these regions improve model prediction of success at opening the boxes when included with total brain size and body mass. Socioecological variables, including measures of social complexity and manual dexterity, failed to predict success at opening the boxes. Our results, thus, fail to support the social brain hypothesis but provide important empirical support for the relationship between relative brain size and the ability to solve this novel technical problem.


2021 ◽  
Vol 9 ◽  
Author(s):  
Rebecca J. Williams ◽  
M. Ethan MacDonald ◽  
Erin L. Mazerolle ◽  
G. Bruce Pike

Elucidating the brain regions and networks associated with cognitive processes has been the mainstay of task-based fMRI, under the assumption that BOLD signals are uncompromised by vascular function. This is despite the plethora of research highlighting BOLD modulations due to vascular changes induced by disease, drugs, and aging. On the other hand, BOLD fMRI-based assessment of cerebrovascular reactivity (CVR) is often used as an indicator of the brain's vascular health and has been shown to be strongly associated with cognitive function. This review paper considers the relationship between BOLD-based assessments of CVR, cognition and task-based fMRI. How the BOLD response reflects both CVR and neural activity, and how findings of altered CVR in disease and in normal physiology are associated with cognition and BOLD signal changes are discussed. These are pertinent considerations for fMRI applications aiming to understand the biological basis of cognition. Therefore, a discussion of how the acquisition of BOLD-based CVR can enhance our ability to map human brain function, with limitations and potential future directions, is presented.


2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Julia Mehlhorn ◽  
Gerd Rehkämper

The relationship between domestication and evolution is still a matter of discussion. In this review, we present some arguments for the assumption that domestication could be seen as an evolutionary process including the possibility that new species might evolve. In course of domestication, many breeds have been developed which show numerous alterations in different parameters such as body size, coloring, habitat, behavior, and brain size and composition. Here, we would like to give an overview particularly about alterations and varieties in (brain) morphology and behavior in domestic poultry and argue that these alterations could be seen as adaptations to the man-made environment.


2021 ◽  
Author(s):  
Victor Nozais ◽  
Stephanie Forkel ◽  
Chris Foulon ◽  
Laurent Petit ◽  
Michel Thiebaut de Schotten

Abstract In recent years, the field of functional neuroimaging has moved from a pure localisationist approach of isolated functional brain regions to a more integrated view of those regions within functional networks. The methods used to investigate such networks, however, rely on local signals in grey matter and are limited in identifying anatomical circuitries supporting the interaction between brain regions. Mapping the brain circuits mediating the functional signal between brain regions would propel forward our understanding of the brain’s functional signatures and dysfunctions. We developed a novel method to unravel the relationship between brain circuits and functions: The Functionnectome. The Functionectome combines the functional signal from fMRI with the anatomy of white matter brain circuits to unlock and chart the first maps of functional white matter. To showcase the versatility of this new method, we provide the first functional white matter maps revealing the joint contribution of connected areas to motor, working memory, and language functions. The Functionnectome comes with an open source companion software and opens new avenues into studying functional networks by applying the method to already existing dataset and beyond task fMRI.


2021 ◽  
pp. 118-142
Author(s):  
Kim E. Ruyle

“The Neuroscience of Learning Agility” explores the relationship between neurobiology and learning agility. It provides an overview of the organization of the brain, focusing on the roles of the limbic system and the prefrontal cortex and how these particular brain regions relate to personality, executive function, and the metacompetencies of emotional intelligence and learning agility. The neuroscience of learning is discussed, including the brain’s attention networks, neuroplasticity, and biological underpinnings of memory. An argument is posited that the brain’s perceptions of threats directly impacts one’s personality and, by extension, influences one’s level of learning agility. The chapter concludes by providing neuroscience-based suggestions for developing learning agility.


Author(s):  
Elisabeth A. Murray ◽  
Steven P. Wise ◽  
Mary K. L. Baldwin ◽  
Kim S. Graham

In the epilogue, a couple of kids befriend a shy stegosaurus; a different stegosaurus worries about the rise of mammals; and a tyrannosaurus presents a situation report. But mainly we consider reptilian brains, the relationship of brain size to intelligence, and the evolutionary success of mammals. Contrary to an internet meme, no one has a “reptilian” or “lizard” brain lurking within. Our entire brain is human. Regarding intelligence, brain organization matters as much as brain size and maybe more. Once dinosaurs became extinct, the mammals that supplanted them had much smaller brains than large dinosaurs had. Instead, the success of mammals depended on the emergence of the neocortex, a new part of the brain. Eventually, this evolutionary innovation came to dominate both the brain and the memories that it contains.


Mind Shift ◽  
2021 ◽  
pp. 46-60
Author(s):  
John Parrington

This chapter investigates the relationship between the individual and society, which has been hotly disputed among philosophers and politicians through the ages. Recent studies have questioned the idea that human beings are naturally solitary individuals. Instead, they suggest that socialising with others is so central to our species that rejection is registered in the same brain regions that respond to physical pain. Other studies have undermined the idea that human beings are inherently selfish, indicating instead that altruistic acts trigger activity in the ‘reward’ region of the brain that is stimulated when a person experiences pleasure. Studies like these raise the question of how the human brain became so attuned to social cues in this way. Here there are two issues to consider. One is evidence that primates in general have evolved to be highly sensitive to social interactions with other members of their species, and this has been accompanied by enhanced brain growth in order to handle these more sophisticated interactions. Yet while social interaction may be hardwired into our brains because of evolutionary changes in our primate ancestors, some features of our strong tendency towards social interaction may be specifically human. The chapter then looks at Russian psychologist Lev Vygotsky’s novel ideas about human consciousness.


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